With development of vehicle-related technologies, many vehicles include various functions for improving a passenger's convenience. However, the more functions a vehicle has, the more operating load a driver experiences. Excessive operating load may deteriorate a driver's concentration on driving, adversely affecting safe driving. Also, as a vehicle includes more functions, a driver's difficulties in operating the vehicle may increase accordingly so that a driver who is inexperienced in operating a vehicle may be not able to properly use all vehicle functions.
In order to overcome these problems, studies into a vehicle-mounted input device for reducing a driver's operating load and difficulties have been conducted. A representative example of such a vehicle-mounted input device is a touch input device capable of detecting a driver's touch inputs. If a vehicle includes such a touch input device, a driver would be able to easily control the vehicle by touching the touch input device without having to perform complicated manipulations.